Re: ESFR heads at airflow openings

Wed, 05 Sep 2007 07:42:37 -0700 

My two cents worth:
First, the velocity limitation is significant. Testing done by FM showed that high velocities near sprinklers could seriously delay operation of EFSRs. Fast response is critical to successful ESFR performance. 


Craig is absolutely correct in saying that lots of organizations make 
the mistake of quoting FM standards as if they were a code. They are 
not. They are developed and distributed for application at FM insured 
locations, subject to the interpretation by FM Engineers. In some cases 
they go beyond NFPA codes because FM's focus is property protection.



Lots of people throw FM standards into their specifications, and lots of 
non-FM Insurance companies use them, as well. The problem is that FM 
standards are not written like codes. FM Engineers interpret them when 
they tailor FM guidelines to site-specific conditions. You should get 
the same from whoever is calling for FM Standards.



When NFPA standards are specified, you have the ability and right to go 
to NFPA and ask for an explanation or interpretation. When FM standards 
are specified, you should have the same right and ability. If the 
location is an FM Insured, you do. If it is not, then whoever is calling 
for FM standards must tell you exactly what he is looking for and why.



In this case, you should tell your client that his insurance company is 
calling for something beyond the specifications. Advise him to go to his 
insurance company and ask for an explanation so he can decide whether he 
should authorize the change his insurance company has asked for.


Joe



[EMAIL PROTECTED] wrote:

Ok, so do you have roof or sidewall exhaust fans?   Any intake plenums
with diffusers, or just an open intake?  What are the sizes of the fan
intakes?

If the fans are roof mounted is the opening level with the underside of
the roof (no plenum), and what relative distance is there (vertically)
between the sprinkler and intake?



Some AHJ's and others think that meeting FM is required just like it's

another Code.  



Craig L. Prahl, CET
Fire Protection Group
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC  29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[EMAIL PROTECTED]
http://www.lg.com


-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bobby
Gillett
Sent: Wednesday, September 05, 2007 9:37 AM
To: [email protected]
Subject: RE: ESFR heads at airflow openings

The insurance carrier is not FM he is just quoting FM and the GC spec's
did not require FM only NFPA-13. I just wanted to have my ducks in a row
before I responded.

They already had the HVAC Eng. calculate the airflow and they say it
requires me to be 30" from the edge of all 7 of the exhaust fans (for
heat removal--no AC). My thinking was in line with yours Craig, if all
of the sudden they want to follow FM - that would be a change to perform
the work.

One of the resolutions, according to FM, is as follows;

2.2.6.2 If it is not possible to meet 2.2.6.1, chose one of the
following

  

options to ensure proper operation
of suppression mode sprinklers in buildings with ceiling-level

    

ventilation:

  

a) Sprinklers Beneath Vent Openings


Install suppression mode sprinklers of the same type used elsewhere in 
the building centered in vent openings having a maximum dimension of 
4.5 ft (1.37 m). This option does not apply to storage of commodities 
greater in hazard than cartoned unexpanded plastic, such as uncartoned 
plastic, aerosols or rolled tissue in buildings higher than 30 ft (9.14
    



  

m).

    


I would have to put a sprinkler in the vent opening, due to spacing
there is no way to move over and be 30" away. I believe this would act
like an obstruction and the one we added would not have an affect on the
other sprinkler spacing-correct?

Bobby Gillett
Project Manager
[EMAIL PROTECTED]
(731)-424-0130
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Wednesday, September 05, 2007 8:27 AM
To: [email protected]
Subject: RE: ESFR heads at airflow openings

The closest thing to that requirement is the table 8.3.2.5(a) which is
dealing with temperature of heads in relation to heat sources, not
specifically ESFR and air velocity.  Other than that I couldn't find
anything related to adjacent air velocities.  (I've got electronic
search capabilities)

First thing I'd do is go back to the GC and state that your contract
directs you to design to NFPA NOT FM.  If the client wants to adhere to
FM standards and did not indicate that in any of the project bid
documents then any extra effort required on your part to meet those
requirements should be an add to your contract.

If you're using ESFR, are you in a open ceiling warehouse or mfg. space?
If that's the case most of your air distribution is probably below your
sprinklers and if so, the discharge velocity of the diffusers should be
inconsequential to your sprinklers as they should be discharging air
downward.  If you have areas where there are either intake or exhaust
louvers or diffusers and they look like they will draw air across your
sprinklers then you'll need the HVAC plans showing the discharge
information on those outlets so you can space heads accordingly.  But
even with that, it's really not up to the sprinkler contractor to
determine what the air velocity is at a given point in space.  You as
the sprinkler contractor shouldn't have to undergo the exercise of
determining when the air velocity drops to or below 5 fps.

Other question is, does the FM guy know what the terminal velocities are
of the air devices in relation to the location of your sprinklers?


Craig L. Prahl, CET
Fire Protection Group
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC  29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[EMAIL PROTECTED]
http://www.lg.com


-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Bobby
Gillett
Sent: Wednesday, September 05, 2007 8:27 AM
To: [email protected]
Subject: ESFR heads at airflow openings

In designing an ESFR system the following is one of the FM requirements;


 


 >2.2.6.1 Coordinate the location of sprinklers and the design of
powered


  

heating, ventilation and air conditioning

    



  

for buildings protected by suppression mode sprinklers so that the air

    



  

velocity at sprinklers does not

    



  

exceed 5 ft/sec (1.52 m/sec).

    



 


I am required, according to job specifications, to design to NFPA-13. I
don't see such a requirement in NFPA-13 or in the listing of the
sprinkler.
Am I missing something? The Insurance agent is now throwing the above
section from FM at us. Suggestions/comments, please.


 


Bobby Gillett

Project Manager

[EMAIL PROTECTED]

(731)-424-0130


 


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